Bump idna from 3.10 to 3.15 in /samples/python

Bumps [idna](https://github.com/kjd/idna) from 3.10 to 3.15.
- [Release notes](https://github.com/kjd/idna/releases)
- [Changelog](https://github.com/kjd/idna/blob/master/HISTORY.md)
- [Commits](kjd/idna@v3.10...v3.15)

---
updated-dependencies:
- dependency-name: idna
  dependency-version: '3.15'
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

samples/python/requirements.txt

@@ -12,7 +12,7 @@ dill==0.3.9
 docopt==0.6.2
 filelock==3.25.0
 Flask==3.1.1
-idna==3.10
+idna==3.15
 idpyoidc==5.0.0
 isort==5.13.2
 itsdangerous==2.2.0